Step 1: Anesthesia Begins at Home

The pet owner begins the continuum of anesthesia with fasting the pet and administering medications as directed by the anesthesia team. Although not all evidence is in agreement, in general, the recommended fast duration for healthy adult patients has decreased. The change is based on clinical experience and experimental evidence of shorter fasting benefits, including a lower incidence of gastroesophageal reflux (GER). An abbreviated fast is particularly important for diabetic and neonatal patients. Most medications currently administered to the pet should be continued on the day of anesthesia, but there are exceptions, especially for some cardiac medications. Analgesic drugs (e.g., nonsteroidal anti-inflammatory drugs [NSAIDs]) may be among the drugs that the patient is already receiving or may be started immediately prior to the procedure. If the patient experiences motion sickness, maropitant should be considered for administration before the patient is transported to the hospital to prevent vomiting. Anxiolytic drugs should definitely be administered for all fractious/aggressive/fearful patients and should be strongly considered for patients that develop any level of fear, anxiety, or stress during a visit to the veterinary hospital. Gabapentin and trazodone are commonly used for this purpose. Dosages for these and other previsit pharmaceuticals are listed in here.

Feeding and treatment recommendations for dogs and cats prior to anesthesia.


Recommendations for Chronic Medications the Day of Anesthesia*


Continue medications as scheduled:

  • Thyroid medication: thyroid supplement or methimazole
  • Behavioral and analgesic medications: sudden withdrawal of these medications is not advised
  • Oral anxiolytics: to reduce fear and anxiety
  • Cardiac medications: pimobendan, furosemide
  • Antibiotics
  • Steroids: should not be abruptly stopped

Discontinue the day of anesthesia:

  • Antihypertensive medication, especially ACE inhibitors: enalapril, benazepril8
  • Anticoagulants: may need to be discontinued 2 wk prior to anesthesia based on risk of bleeding

Administer based on specific recommendations to owner:

  • Insulin: full dose should not be administered to fasted patients because of risk of hypoglycemia

*List is not all-inclusive but focuses on medications strongly recommended to either administer or cease.

ACE, angiotensin-converting enzyme.

These guidelines are supported by generous educational grants from IDEXX Laboratories, Inc., Midmark, and Zoetis Petcare.